feat: Extend --filesystem flag to start-api and start-lambda commands…

samcli/commands/local/cli_common/options.py

@@ -212,6 +212,13 @@ def invoke_common_options(f):
                 help="Specify the location basedir where the lambda layers used by the template will be downloaded to.",
                 default=get_default_layer_cache_dir(),
             ),
+            click.option(
+                "--filesystem",
+                type=click.Path(exists=True, file_okay=False, dir_okay=True, resolve_path=True),
+                help="Local directory to mount as EFS filesystem for Lambda functions. "
+                "Maps to the LocalMountPath specified in the function's FileSystemConfigs. "
+                "If no FileSystemConfigs is specified, defaults to /mnt/efs",
+            ),
         ]
         + docker_click_options()
         + [

samcli/commands/local/invoke/cli.py

@@ -100,6 +100,7 @@ def cli(
     docker_network,
     log_file,
     layer_cache_basedir,
+    filesystem,
     skip_pull_image,
     force_image_build,
     shutdown,
@@ -138,6 +139,7 @@ def cli(
         docker_network,
         log_file,
         layer_cache_basedir,
+        filesystem,
         skip_pull_image,
         force_image_build,
         shutdown,
@@ -168,6 +170,7 @@ def do_cli(  # pylint: disable=R0914
     docker_network,
     log_file,
     layer_cache_basedir,
+    filesystem,
     skip_pull_image,
     force_image_build,
     shutdown,

samcli/commands/local/invoke/core/options.py

@@ -36,6 +36,7 @@
     "add_host",
     "invoke_image",
     "runtime",
+    "filesystem",
     "mount_symlinks",
     "no_memory_limit",
 ]

samcli/commands/local/start_api/cli.py

@@ -123,6 +123,7 @@ def cli(
     docker_network,
     log_file,
     layer_cache_basedir,
+    filesystem,
     skip_pull_image,
     force_image_build,
     parameter_overrides,
@@ -164,6 +165,7 @@ def cli(
         docker_network,
         log_file,
         layer_cache_basedir,
+        filesystem,
         skip_pull_image,
         force_image_build,
         parameter_overrides,
@@ -197,6 +199,7 @@ def do_cli(  # pylint: disable=R0914
     docker_network,
     log_file,
     layer_cache_basedir,
+    filesystem,
     skip_pull_image,
     force_image_build,
     parameter_overrides,
@@ -256,6 +259,7 @@ def do_cli(  # pylint: disable=R0914
             container_host_interface=container_host_interface,
             invoke_images=processed_invoke_images,
             add_host=add_host,
+            filesystem_dir=filesystem,
             no_mem_limit=no_mem_limit,
         ) as invoke_context:
             ssl_context = (ssl_cert_file, ssl_key_file) if ssl_cert_file else None

samcli/commands/local/start_api/core/options.py

@@ -34,6 +34,7 @@
     "docker_volume_basedir",
     "skip_pull_image",
     "docker_network",
+    "filesystem",
     "force_image_build",
     "no_memory_limit",
     "warm_containers",

samcli/commands/local/start_lambda/cli.py

@@ -85,6 +85,7 @@ def cli(
     docker_network,
     log_file,
     layer_cache_basedir,
+    filesystem,
     skip_pull_image,
     force_image_build,
     parameter_overrides,
@@ -122,6 +123,7 @@ def cli(
         docker_network,
         log_file,
         layer_cache_basedir,
+        filesystem,
         skip_pull_image,
         force_image_build,
         parameter_overrides,
@@ -151,6 +153,7 @@ def do_cli(  # pylint: disable=R0914
     docker_network,
     log_file,
     layer_cache_basedir,
+    filesystem,
     skip_pull_image,
     force_image_build,
     parameter_overrides,
@@ -208,6 +211,7 @@ def do_cli(  # pylint: disable=R0914
             container_host_interface=container_host_interface,
             add_host=add_host,
             invoke_images=processed_invoke_images,
+            filesystem_dir=filesystem,
             no_mem_limit=no_mem_limit,
         ) as invoke_context:
             service = LocalLambdaService(lambda_invoke_context=invoke_context, port=port, host=host)

samcli/commands/local/start_lambda/core/options.py

@@ -31,6 +31,7 @@
     "docker_volume_basedir",
     "skip_pull_image",
     "docker_network",
+    "filesystem",
     "force_image_build",
     "shutdown",
     "container_host",

tests/integration/local/start_api/test_filesystem_mount.py

@@ -0,0 +1,94 @@
+"""
+Integration tests for --filesystem flag with start-api command
+Tests that the --filesystem flag correctly mounts EFS directories and allows Lambda functions
+to interact with the mounted filesystem.
+"""
+
+import os
+import shutil
+import tempfile
+from pathlib import Path
+
+import pytest
+import requests
+
+from tests.integration.local.start_api.start_api_integ_base import StartApiIntegBaseClass
+
+
+class TestFilesystemMountWithStartApi(StartApiIntegBaseClass):
+    """
+    Test that --filesystem flag correctly mounts EFS directories for start-api
+    """
+
+    template_path = "/testdata/start_api/filesystem/template.yaml"
+
+    def setUp(self):
+        self.url = f"http://127.0.0.1:{self.port}"
+
+        # Create a temporary filesystem directory with test files
+        self.test_fs_dir = tempfile.mkdtemp()
+        self.test_file = Path(self.test_fs_dir) / "test.txt"
+        self.test_file.write_text("Hello from EFS!")
+
+    def tearDown(self):
+        # Clean up test filesystem
+        if os.path.exists(self.test_fs_dir):
+            shutil.rmtree(self.test_fs_dir)
+        super().tearDown()
+
+    @property
+    def command_list(self):
+        command_list = super().command_list
+        # Add filesystem flag pointing to our test directory
+        command_list.extend(["--filesystem", self.test_fs_dir])
+        return command_list
+
+    @pytest.mark.flaky(reruns=3)
+    @pytest.mark.timeout(timeout=600, method="thread")
+    def test_lambda_can_read_from_mounted_filesystem(self):
+        """
+        Test that Lambda function can read files from mounted EFS directory
+        """
+        response = requests.get(f"{self.url}/read-file", params={"filename": "test.txt"}, timeout=300)
+
+        self.assertEqual(response.status_code, 200)
+        data = response.json()
+        self.assertEqual(data.get("content"), "Hello from EFS!")
+        self.assertEqual(data.get("success"), True)
+        self.assertEqual(data.get("filename"), "test.txt")
+
+    @pytest.mark.flaky(reruns=3)
+    @pytest.mark.timeout(timeout=600, method="thread")
+    def test_lambda_can_write_to_mounted_filesystem(self):
+        """
+        Test that Lambda function can write files to mounted EFS directory
+        and verify changes persist on host filesystem
+        """
+        write_content = "Written from Lambda!"
+        response = requests.post(
+            f"{self.url}/write-file", json={"filename": "written.txt", "content": write_content}, timeout=300
+        )
+
+        self.assertEqual(response.status_code, 200)
+        data = response.json()
+        self.assertEqual(data.get("success"), True)
+        self.assertEqual(data.get("filename"), "written.txt")
+
+        # Verify file actually exists on host filesystem
+        written_file = Path(self.test_fs_dir) / "written.txt"
+        self.assertTrue(written_file.exists(), "File should exist on host filesystem after Lambda write")
+        self.assertEqual(written_file.read_text(), write_content, "File content should match what Lambda wrote")
+
+    @pytest.mark.flaky(reruns=3)
+    @pytest.mark.timeout(timeout=600, method="thread")
+    def test_lambda_can_list_mounted_filesystem(self):
+        """
+        Test that Lambda function can list directory contents of mounted EFS
+        """
+        response = requests.get(f"{self.url}/list-files", timeout=300)
+
+        self.assertEqual(response.status_code, 200)
+        data = response.json()
+        self.assertEqual(data.get("success"), True)
+        self.assertIn("test.txt", data.get("files", []), "test.txt should be visible to Lambda in mounted filesystem")
+        self.assertEqual(data.get("mount_path"), "/mnt/efs", "Mount path should be /mnt/efs")

tests/integration/local/start_api/testdata/filesystem/code/main.py

@@ -0,0 +1,50 @@
+import json
+import os
+
+EFS_MOUNT = "/mnt/efs"
+
+
+def handler(event, context):
+    """
+    Lambda handler for testing EFS filesystem mounting
+    """
+    path = event.get("path", "")
+
+    if path == "/read-file":
+        # Read a file from mounted EFS
+        filename = event.get("queryStringParameters", {}).get("filename", "")
+        try:
+            filepath = os.path.join(EFS_MOUNT, filename)
+            with open(filepath, "r") as f:
+                content = f.read()
+            return {
+                "statusCode": 200,
+                "body": json.dumps({"success": True, "content": content, "filename": filename}),
+            }
+        except Exception as e:
+            return {"statusCode": 500, "body": json.dumps({"success": False, "error": str(e)})}
+
+    elif path == "/write-file":
+        # Write a file to mounted EFS
+        try:
+            body = json.loads(event.get("body", "{}"))
+            filename = body.get("filename", "")
+            content = body.get("content", "")
+
+            filepath = os.path.join(EFS_MOUNT, filename)
+            with open(filepath, "w") as f:
+                f.write(content)
+
+            return {"statusCode": 200, "body": json.dumps({"success": True, "filename": filename})}
+        except Exception as e:
+            return {"statusCode": 500, "body": json.dumps({"success": False, "error": str(e)})}
+
+    elif path == "/list-files":
+        # List files in mounted EFS
+        try:
+            files = os.listdir(EFS_MOUNT)
+            return {"statusCode": 200, "body": json.dumps({"success": True, "files": files, "mount_path": EFS_MOUNT})}
+        except Exception as e:
+            return {"statusCode": 500, "body": json.dumps({"success": False, "error": str(e)})}
+
+    return {"statusCode": 404, "body": json.dumps({"error": "Not found"})}

tests/integration/local/start_api/testdata/filesystem/template.yaml

@@ -0,0 +1,30 @@
+AWSTemplateFormatVersion: '2010-09-09'
+Transform: AWS::Serverless-2016-10-31
+
+Resources:
+  FileSystemFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+      Handler: main.handler
+      Runtime: python3.11
+      CodeUri: code/
+      Timeout: 30
+      FileSystemConfigs:
+        - Arn: "arn:aws:elasticfilesystem:us-east-1:123456789012:access-point/fsap-test"
+          LocalMountPath: "/mnt/efs"
+      Events:
+        ReadFile:
+          Type: Api
+          Properties:
+            Path: /read-file
+            Method: GET
+        WriteFile:
+          Type: Api
+          Properties:
+            Path: /write-file
+            Method: POST
+        ListFiles:
+          Type: Api
+          Properties:
+            Path: /list-files
+            Method: GET

tests/unit/commands/local/cli_common/test_invoke_context.py

@@ -1401,7 +1401,12 @@ def test_must_pass_custom_region(self, add_account_id_to_global_mock, get_stacks
 
 
 class TestInvokeContext_add_account_id_to_global(TestCase):
-    def test_must_work_with_no_token(self):
+    @patch("samcli.commands.local.cli_common.invoke_context.get_boto_client_provider_with_config")
+    def test_must_work_with_no_token(self, get_boto_client_provider_with_config_mock):
+        # Mock to return no credentials
+        get_boto_client_provider_with_config_mock.return_value.return_value.get_caller_identity.side_effect = Exception(
+            "No credentials"
+        )
         invoke_context = InvokeContext("template_file")
         invoke_context._add_account_id_to_global()
         self.assertIsNone(invoke_context._global_parameter_overrides)

tests/unit/commands/local/invoke/test_cli.py

@@ -53,6 +53,7 @@ def setUp(self):
         self.overide_runtime = None
         self.mount_symlinks = False
         self.no_mem_limit = False
+        self.filesystem = None
 
         self.ctx_mock = Mock()
         self.ctx_mock.region = self.region_name
@@ -73,9 +74,10 @@ def call_cli(self):
             docker_volume_basedir=self.docker_volume_basedir,
             docker_network=self.docker_network,
             log_file=self.log_file,
+            layer_cache_basedir=self.layer_cache_basedir,
+            filesystem=self.filesystem,
             skip_pull_image=self.skip_pull_image,
             parameter_overrides=self.parameter_overrides,
-            layer_cache_basedir=self.layer_cache_basedir,
             force_image_build=self.force_image_build,
             shutdown=self.shutdown,
             container_host=self.container_host,
@@ -161,9 +163,9 @@ def test_cli_must_invoke_with_no_event(self, get_event_mock, InvokeContextMock):
             parameter_overrides=self.parameter_overrides,
             layer_cache_basedir=self.layer_cache_basedir,
             force_image_build=self.force_image_build,
-            shutdown=self.shutdown,
             aws_region=self.region_name,
             aws_profile=self.profile,
+            shutdown=self.shutdown,
             container_host=self.container_host,
             container_host_interface=self.container_host_interface,
             add_host=self.add_host,